There was a time that boxing, horse racing and baseball were the only three professional sports that mattered in the United States.
Those days are long over. In boxing's case, it is in a straight-up fight for survival, as many of the top combat athletes have gone to mixed martial arts, and the legendary boxing matchups that used to rule the sports world are few and far between.
The sweet science of boxing is often a battle of strategy and will when top fighters get together. However, strategy doesn't always come into play. Sometimes the stronger and more powerful puncher just blows through his opponent and scores a knockout in the first round.
Here's a look at six of the most meaningful and impressive first-round KOs in boxing history.
Note that you won't see Muhammad Ali's first-round KO over Sonny Liston in this piece because of the controversial ending to that fight. While some claim that Ali's quick right hand that put Liston away was a clean punch, others say it wasn't hard enough to crush a grape and Liston went down out of convenience. With that in mind, the controversy holds it back from ranking with the fights we have listed.